diff options
Diffstat (limited to 'drivers/md/dm-cache-metadata.c')
| -rw-r--r-- | drivers/md/dm-cache-metadata.c | 1868 |
1 files changed, 1868 insertions, 0 deletions
diff --git a/drivers/md/dm-cache-metadata.c b/drivers/md/dm-cache-metadata.c new file mode 100644 index 0000000000..acffed750e --- /dev/null +++ b/drivers/md/dm-cache-metadata.c @@ -0,0 +1,1868 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Copyright (C) 2012 Red Hat, Inc. + * + * This file is released under the GPL. + */ + +#include "dm-cache-metadata.h" + +#include "persistent-data/dm-array.h" +#include "persistent-data/dm-bitset.h" +#include "persistent-data/dm-space-map.h" +#include "persistent-data/dm-space-map-disk.h" +#include "persistent-data/dm-transaction-manager.h" + +#include <linux/device-mapper.h> +#include <linux/refcount.h> + +/*----------------------------------------------------------------*/ + +#define DM_MSG_PREFIX "cache metadata" + +#define CACHE_SUPERBLOCK_MAGIC 06142003 +#define CACHE_SUPERBLOCK_LOCATION 0 + +/* + * defines a range of metadata versions that this module can handle. + */ +#define MIN_CACHE_VERSION 1 +#define MAX_CACHE_VERSION 2 + +/* + * 3 for btree insert + + * 2 for btree lookup used within space map + */ +#define CACHE_MAX_CONCURRENT_LOCKS 5 +#define SPACE_MAP_ROOT_SIZE 128 + +enum superblock_flag_bits { + /* for spotting crashes that would invalidate the dirty bitset */ + CLEAN_SHUTDOWN, + /* metadata must be checked using the tools */ + NEEDS_CHECK, +}; + +/* + * Each mapping from cache block -> origin block carries a set of flags. + */ +enum mapping_bits { + /* + * A valid mapping. Because we're using an array we clear this + * flag for an non existant mapping. + */ + M_VALID = 1, + + /* + * The data on the cache is different from that on the origin. + * This flag is only used by metadata format 1. + */ + M_DIRTY = 2 +}; + +struct cache_disk_superblock { + __le32 csum; + __le32 flags; + __le64 blocknr; + + __u8 uuid[16]; + __le64 magic; + __le32 version; + + __u8 policy_name[CACHE_POLICY_NAME_SIZE]; + __le32 policy_hint_size; + + __u8 metadata_space_map_root[SPACE_MAP_ROOT_SIZE]; + __le64 mapping_root; + __le64 hint_root; + + __le64 discard_root; + __le64 discard_block_size; + __le64 discard_nr_blocks; + + __le32 data_block_size; + __le32 metadata_block_size; + __le32 cache_blocks; + + __le32 compat_flags; + __le32 compat_ro_flags; + __le32 incompat_flags; + + __le32 read_hits; + __le32 read_misses; + __le32 write_hits; + __le32 write_misses; + + __le32 policy_version[CACHE_POLICY_VERSION_SIZE]; + + /* + * Metadata format 2 fields. + */ + __le64 dirty_root; +} __packed; + +struct dm_cache_metadata { + refcount_t ref_count; + struct list_head list; + + unsigned int version; + struct block_device *bdev; + struct dm_block_manager *bm; + struct dm_space_map *metadata_sm; + struct dm_transaction_manager *tm; + + struct dm_array_info info; + struct dm_array_info hint_info; + struct dm_disk_bitset discard_info; + + struct rw_semaphore root_lock; + unsigned long flags; + dm_block_t root; + dm_block_t hint_root; + dm_block_t discard_root; + + sector_t discard_block_size; + dm_dblock_t discard_nr_blocks; + + sector_t data_block_size; + dm_cblock_t cache_blocks; + bool changed:1; + bool clean_when_opened:1; + + char policy_name[CACHE_POLICY_NAME_SIZE]; + unsigned int policy_version[CACHE_POLICY_VERSION_SIZE]; + size_t policy_hint_size; + struct dm_cache_statistics stats; + + /* + * Reading the space map root can fail, so we read it into this + * buffer before the superblock is locked and updated. + */ + __u8 metadata_space_map_root[SPACE_MAP_ROOT_SIZE]; + + /* + * Set if a transaction has to be aborted but the attempt to roll + * back to the previous (good) transaction failed. The only + * metadata operation permissible in this state is the closing of + * the device. + */ + bool fail_io:1; + + /* + * Metadata format 2 fields. + */ + dm_block_t dirty_root; + struct dm_disk_bitset dirty_info; + + /* + * These structures are used when loading metadata. They're too + * big to put on the stack. + */ + struct dm_array_cursor mapping_cursor; + struct dm_array_cursor hint_cursor; + struct dm_bitset_cursor dirty_cursor; +}; + +/* + *----------------------------------------------------------------- + * superblock validator + *----------------------------------------------------------------- + */ +#define SUPERBLOCK_CSUM_XOR 9031977 + +static void sb_prepare_for_write(struct dm_block_validator *v, + struct dm_block *b, + size_t sb_block_size) +{ + struct cache_disk_superblock *disk_super = dm_block_data(b); + + disk_super->blocknr = cpu_to_le64(dm_block_location(b)); + disk_super->csum = cpu_to_le32(dm_bm_checksum(&disk_super->flags, + sb_block_size - sizeof(__le32), + SUPERBLOCK_CSUM_XOR)); +} + +static int check_metadata_version(struct cache_disk_superblock *disk_super) +{ + uint32_t metadata_version = le32_to_cpu(disk_super->version); + + if (metadata_version < MIN_CACHE_VERSION || metadata_version > MAX_CACHE_VERSION) { + DMERR("Cache metadata version %u found, but only versions between %u and %u supported.", + metadata_version, MIN_CACHE_VERSION, MAX_CACHE_VERSION); + return -EINVAL; + } + + return 0; +} + +static int sb_check(struct dm_block_validator *v, + struct dm_block *b, + size_t sb_block_size) +{ + struct cache_disk_superblock *disk_super = dm_block_data(b); + __le32 csum_le; + + if (dm_block_location(b) != le64_to_cpu(disk_super->blocknr)) { + DMERR("%s failed: blocknr %llu: wanted %llu", + __func__, le64_to_cpu(disk_super->blocknr), + (unsigned long long)dm_block_location(b)); + return -ENOTBLK; + } + + if (le64_to_cpu(disk_super->magic) != CACHE_SUPERBLOCK_MAGIC) { + DMERR("%s failed: magic %llu: wanted %llu", + __func__, le64_to_cpu(disk_super->magic), + (unsigned long long)CACHE_SUPERBLOCK_MAGIC); + return -EILSEQ; + } + + csum_le = cpu_to_le32(dm_bm_checksum(&disk_super->flags, + sb_block_size - sizeof(__le32), + SUPERBLOCK_CSUM_XOR)); + if (csum_le != disk_super->csum) { + DMERR("%s failed: csum %u: wanted %u", + __func__, le32_to_cpu(csum_le), le32_to_cpu(disk_super->csum)); + return -EILSEQ; + } + + return check_metadata_version(disk_super); +} + +static struct dm_block_validator sb_validator = { + .name = "superblock", + .prepare_for_write = sb_prepare_for_write, + .check = sb_check +}; + +/*----------------------------------------------------------------*/ + +static int superblock_read_lock(struct dm_cache_metadata *cmd, + struct dm_block **sblock) +{ + return dm_bm_read_lock(cmd->bm, CACHE_SUPERBLOCK_LOCATION, + &sb_validator, sblock); +} + +static int superblock_lock_zero(struct dm_cache_metadata *cmd, + struct dm_block **sblock) +{ + return dm_bm_write_lock_zero(cmd->bm, CACHE_SUPERBLOCK_LOCATION, + &sb_validator, sblock); +} + +static int superblock_lock(struct dm_cache_metadata *cmd, + struct dm_block **sblock) +{ + return dm_bm_write_lock(cmd->bm, CACHE_SUPERBLOCK_LOCATION, + &sb_validator, sblock); +} + +/*----------------------------------------------------------------*/ + +static int __superblock_all_zeroes(struct dm_block_manager *bm, bool *result) +{ + int r; + unsigned int i; + struct dm_block *b; + __le64 *data_le, zero = cpu_to_le64(0); + unsigned int sb_block_size = dm_bm_block_size(bm) / sizeof(__le64); + + /* + * We can't use a validator here - it may be all zeroes. + */ + r = dm_bm_read_lock(bm, CACHE_SUPERBLOCK_LOCATION, NULL, &b); + if (r) + return r; + + data_le = dm_block_data(b); + *result = true; + for (i = 0; i < sb_block_size; i++) { + if (data_le[i] != zero) { + *result = false; + break; + } + } + + dm_bm_unlock(b); + + return 0; +} + +static void __setup_mapping_info(struct dm_cache_metadata *cmd) +{ + struct dm_btree_value_type vt; + + vt.context = NULL; + vt.size = sizeof(__le64); + vt.inc = NULL; + vt.dec = NULL; + vt.equal = NULL; + dm_array_info_init(&cmd->info, cmd->tm, &vt); + + if (cmd->policy_hint_size) { + vt.size = sizeof(__le32); + dm_array_info_init(&cmd->hint_info, cmd->tm, &vt); + } +} + +static int __save_sm_root(struct dm_cache_metadata *cmd) +{ + int r; + size_t metadata_len; + + r = dm_sm_root_size(cmd->metadata_sm, &metadata_len); + if (r < 0) + return r; + + return dm_sm_copy_root(cmd->metadata_sm, &cmd->metadata_space_map_root, + metadata_len); +} + +static void __copy_sm_root(struct dm_cache_metadata *cmd, + struct cache_disk_superblock *disk_super) +{ + memcpy(&disk_super->metadata_space_map_root, + &cmd->metadata_space_map_root, + sizeof(cmd->metadata_space_map_root)); +} + +static bool separate_dirty_bits(struct dm_cache_metadata *cmd) +{ + return cmd->version >= 2; +} + +static int __write_initial_superblock(struct dm_cache_metadata *cmd) +{ + int r; + struct dm_block *sblock; + struct cache_disk_superblock *disk_super; + sector_t bdev_size = bdev_nr_sectors(cmd->bdev); + + /* FIXME: see if we can lose the max sectors limit */ + if (bdev_size > DM_CACHE_METADATA_MAX_SECTORS) + bdev_size = DM_CACHE_METADATA_MAX_SECTORS; + + r = dm_tm_pre_commit(cmd->tm); + if (r < 0) + return r; + + /* + * dm_sm_copy_root() can fail. So we need to do it before we start + * updating the superblock. + */ + r = __save_sm_root(cmd); + if (r) + return r; + + r = superblock_lock_zero(cmd, &sblock); + if (r) + return r; + + disk_super = dm_block_data(sblock); + disk_super->flags = 0; + memset(disk_super->uuid, 0, sizeof(disk_super->uuid)); + disk_super->magic = cpu_to_le64(CACHE_SUPERBLOCK_MAGIC); + disk_super->version = cpu_to_le32(cmd->version); + memset(disk_super->policy_name, 0, sizeof(disk_super->policy_name)); + memset(disk_super->policy_version, 0, sizeof(disk_super->policy_version)); + disk_super->policy_hint_size = cpu_to_le32(0); + + __copy_sm_root(cmd, disk_super); + + disk_super->mapping_root = cpu_to_le64(cmd->root); + disk_super->hint_root = cpu_to_le64(cmd->hint_root); + disk_super->discard_root = cpu_to_le64(cmd->discard_root); + disk_super->discard_block_size = cpu_to_le64(cmd->discard_block_size); + disk_super->discard_nr_blocks = cpu_to_le64(from_dblock(cmd->discard_nr_blocks)); + disk_super->metadata_block_size = cpu_to_le32(DM_CACHE_METADATA_BLOCK_SIZE); + disk_super->data_block_size = cpu_to_le32(cmd->data_block_size); + disk_super->cache_blocks = cpu_to_le32(0); + + disk_super->read_hits = cpu_to_le32(0); + disk_super->read_misses = cpu_to_le32(0); + disk_super->write_hits = cpu_to_le32(0); + disk_super->write_misses = cpu_to_le32(0); + + if (separate_dirty_bits(cmd)) + disk_super->dirty_root = cpu_to_le64(cmd->dirty_root); + + return dm_tm_commit(cmd->tm, sblock); +} + +static int __format_metadata(struct dm_cache_metadata *cmd) +{ + int r; + + r = dm_tm_create_with_sm(cmd->bm, CACHE_SUPERBLOCK_LOCATION, + &cmd->tm, &cmd->metadata_sm); + if (r < 0) { + DMERR("tm_create_with_sm failed"); + return r; + } + + __setup_mapping_info(cmd); + + r = dm_array_empty(&cmd->info, &cmd->root); + if (r < 0) + goto bad; + + if (separate_dirty_bits(cmd)) { + dm_disk_bitset_init(cmd->tm, &cmd->dirty_info); + r = dm_bitset_empty(&cmd->dirty_info, &cmd->dirty_root); + if (r < 0) + goto bad; + } + + dm_disk_bitset_init(cmd->tm, &cmd->discard_info); + r = dm_bitset_empty(&cmd->discard_info, &cmd->discard_root); + if (r < 0) + goto bad; + + cmd->discard_block_size = 0; + cmd->discard_nr_blocks = 0; + + r = __write_initial_superblock(cmd); + if (r) + goto bad; + + cmd->clean_when_opened = true; + return 0; + +bad: + dm_tm_destroy(cmd->tm); + dm_sm_destroy(cmd->metadata_sm); + + return r; +} + +static int __check_incompat_features(struct cache_disk_superblock *disk_super, + struct dm_cache_metadata *cmd) +{ + uint32_t incompat_flags, features; + + incompat_flags = le32_to_cpu(disk_super->incompat_flags); + features = incompat_flags & ~DM_CACHE_FEATURE_INCOMPAT_SUPP; + if (features) { + DMERR("could not access metadata due to unsupported optional features (%lx).", + (unsigned long)features); + return -EINVAL; + } + + /* + * Check for read-only metadata to skip the following RDWR checks. + */ + if (bdev_read_only(cmd->bdev)) + return 0; + + features = le32_to_cpu(disk_super->compat_ro_flags) & ~DM_CACHE_FEATURE_COMPAT_RO_SUPP; + if (features) { + DMERR("could not access metadata RDWR due to unsupported optional features (%lx).", + (unsigned long)features); + return -EINVAL; + } + + return 0; +} + +static int __open_metadata(struct dm_cache_metadata *cmd) +{ + int r; + struct dm_block *sblock; + struct cache_disk_superblock *disk_super; + unsigned long sb_flags; + + r = superblock_read_lock(cmd, &sblock); + if (r < 0) { + DMERR("couldn't read lock superblock"); + return r; + } + + disk_super = dm_block_data(sblock); + + /* Verify the data block size hasn't changed */ + if (le32_to_cpu(disk_super->data_block_size) != cmd->data_block_size) { + DMERR("changing the data block size (from %u to %llu) is not supported", + le32_to_cpu(disk_super->data_block_size), + (unsigned long long)cmd->data_block_size); + r = -EINVAL; + goto bad; + } + + r = __check_incompat_features(disk_super, cmd); + if (r < 0) + goto bad; + + r = dm_tm_open_with_sm(cmd->bm, CACHE_SUPERBLOCK_LOCATION, + disk_super->metadata_space_map_root, + sizeof(disk_super->metadata_space_map_root), + &cmd->tm, &cmd->metadata_sm); + if (r < 0) { + DMERR("tm_open_with_sm failed"); + goto bad; + } + + __setup_mapping_info(cmd); + dm_disk_bitset_init(cmd->tm, &cmd->dirty_info); + dm_disk_bitset_init(cmd->tm, &cmd->discard_info); + sb_flags = le32_to_cpu(disk_super->flags); + cmd->clean_when_opened = test_bit(CLEAN_SHUTDOWN, &sb_flags); + dm_bm_unlock(sblock); + + return 0; + +bad: + dm_bm_unlock(sblock); + return r; +} + +static int __open_or_format_metadata(struct dm_cache_metadata *cmd, + bool format_device) +{ + int r; + bool unformatted = false; + + r = __superblock_all_zeroes(cmd->bm, &unformatted); + if (r) + return r; + + if (unformatted) + return format_device ? __format_metadata(cmd) : -EPERM; + + return __open_metadata(cmd); +} + +static int __create_persistent_data_objects(struct dm_cache_metadata *cmd, + bool may_format_device) +{ + int r; + + cmd->bm = dm_block_manager_create(cmd->bdev, DM_CACHE_METADATA_BLOCK_SIZE << SECTOR_SHIFT, + CACHE_MAX_CONCURRENT_LOCKS); + if (IS_ERR(cmd->bm)) { + DMERR("could not create block manager"); + r = PTR_ERR(cmd->bm); + cmd->bm = NULL; + return r; + } + + r = __open_or_format_metadata(cmd, may_format_device); + if (r) { + dm_block_manager_destroy(cmd->bm); + cmd->bm = NULL; + } + + return r; +} + +static void __destroy_persistent_data_objects(struct dm_cache_metadata *cmd, + bool destroy_bm) +{ + dm_sm_destroy(cmd->metadata_sm); + dm_tm_destroy(cmd->tm); + if (destroy_bm) + dm_block_manager_destroy(cmd->bm); +} + +typedef unsigned long (*flags_mutator)(unsigned long); + +static void update_flags(struct cache_disk_superblock *disk_super, + flags_mutator mutator) +{ + uint32_t sb_flags = mutator(le32_to_cpu(disk_super->flags)); + + disk_super->flags = cpu_to_le32(sb_flags); +} + +static unsigned long set_clean_shutdown(unsigned long flags) +{ + set_bit(CLEAN_SHUTDOWN, &flags); + return flags; +} + +static unsigned long clear_clean_shutdown(unsigned long flags) +{ + clear_bit(CLEAN_SHUTDOWN, &flags); + return flags; +} + +static void read_superblock_fields(struct dm_cache_metadata *cmd, + struct cache_disk_superblock *disk_super) +{ + cmd->version = le32_to_cpu(disk_super->version); + cmd->flags = le32_to_cpu(disk_super->flags); + cmd->root = le64_to_cpu(disk_super->mapping_root); + cmd->hint_root = le64_to_cpu(disk_super->hint_root); + cmd->discard_root = le64_to_cpu(disk_super->discard_root); + cmd->discard_block_size = le64_to_cpu(disk_super->discard_block_size); + cmd->discard_nr_blocks = to_dblock(le64_to_cpu(disk_super->discard_nr_blocks)); + cmd->data_block_size = le32_to_cpu(disk_super->data_block_size); + cmd->cache_blocks = to_cblock(le32_to_cpu(disk_super->cache_blocks)); + strncpy(cmd->policy_name, disk_super->policy_name, sizeof(cmd->policy_name)); + cmd->policy_version[0] = le32_to_cpu(disk_super->policy_version[0]); + cmd->policy_version[1] = le32_to_cpu(disk_super->policy_version[1]); + cmd->policy_version[2] = le32_to_cpu(disk_super->policy_version[2]); + cmd->policy_hint_size = le32_to_cpu(disk_super->policy_hint_size); + + cmd->stats.read_hits = le32_to_cpu(disk_super->read_hits); + cmd->stats.read_misses = le32_to_cpu(disk_super->read_misses); + cmd->stats.write_hits = le32_to_cpu(disk_super->write_hits); + cmd->stats.write_misses = le32_to_cpu(disk_super->write_misses); + + if (separate_dirty_bits(cmd)) + cmd->dirty_root = le64_to_cpu(disk_super->dirty_root); + + cmd->changed = false; +} + +/* + * The mutator updates the superblock flags. + */ +static int __begin_transaction_flags(struct dm_cache_metadata *cmd, + flags_mutator mutator) +{ + int r; + struct cache_disk_superblock *disk_super; + struct dm_block *sblock; + + r = superblock_lock(cmd, &sblock); + if (r) + return r; + + disk_super = dm_block_data(sblock); + update_flags(disk_super, mutator); + read_superblock_fields(cmd, disk_super); + dm_bm_unlock(sblock); + + return dm_bm_flush(cmd->bm); +} + +static int __begin_transaction(struct dm_cache_metadata *cmd) +{ + int r; + struct cache_disk_superblock *disk_super; + struct dm_block *sblock; + + /* + * We re-read the superblock every time. Shouldn't need to do this + * really. + */ + r = superblock_read_lock(cmd, &sblock); + if (r) + return r; + + disk_super = dm_block_data(sblock); + read_superblock_fields(cmd, disk_super); + dm_bm_unlock(sblock); + + return 0; +} + +static int __commit_transaction(struct dm_cache_metadata *cmd, + flags_mutator mutator) +{ + int r; + struct cache_disk_superblock *disk_super; + struct dm_block *sblock; + + /* + * We need to know if the cache_disk_superblock exceeds a 512-byte sector. + */ + BUILD_BUG_ON(sizeof(struct cache_disk_superblock) > 512); + + if (separate_dirty_bits(cmd)) { + r = dm_bitset_flush(&cmd->dirty_info, cmd->dirty_root, + &cmd->dirty_root); + if (r) + return r; + } + + r = dm_bitset_flush(&cmd->discard_info, cmd->discard_root, + &cmd->discard_root); + if (r) + return r; + + r = dm_tm_pre_commit(cmd->tm); + if (r < 0) + return r; + + r = __save_sm_root(cmd); + if (r) + return r; + + r = superblock_lock(cmd, &sblock); + if (r) + return r; + + disk_super = dm_block_data(sblock); + + disk_super->flags = cpu_to_le32(cmd->flags); + if (mutator) + update_flags(disk_super, mutator); + + disk_super->mapping_root = cpu_to_le64(cmd->root); + if (separate_dirty_bits(cmd)) + disk_super->dirty_root = cpu_to_le64(cmd->dirty_root); + disk_super->hint_root = cpu_to_le64(cmd->hint_root); + disk_super->discard_root = cpu_to_le64(cmd->discard_root); + disk_super->discard_block_size = cpu_to_le64(cmd->discard_block_size); + disk_super->discard_nr_blocks = cpu_to_le64(from_dblock(cmd->discard_nr_blocks)); + disk_super->cache_blocks = cpu_to_le32(from_cblock(cmd->cache_blocks)); + strncpy(disk_super->policy_name, cmd->policy_name, sizeof(disk_super->policy_name)); + disk_super->policy_version[0] = cpu_to_le32(cmd->policy_version[0]); + disk_super->policy_version[1] = cpu_to_le32(cmd->policy_version[1]); + disk_super->policy_version[2] = cpu_to_le32(cmd->policy_version[2]); + disk_super->policy_hint_size = cpu_to_le32(cmd->policy_hint_size); + + disk_super->read_hits = cpu_to_le32(cmd->stats.read_hits); + disk_super->read_misses = cpu_to_le32(cmd->stats.read_misses); + disk_super->write_hits = cpu_to_le32(cmd->stats.write_hits); + disk_super->write_misses = cpu_to_le32(cmd->stats.write_misses); + __copy_sm_root(cmd, disk_super); + + return dm_tm_commit(cmd->tm, sblock); +} + +/*----------------------------------------------------------------*/ + +/* + * The mappings are held in a dm-array that has 64-bit values stored in + * little-endian format. The index is the cblock, the high 48bits of the + * value are the oblock and the low 16 bit the flags. + */ +#define FLAGS_MASK ((1 << 16) - 1) + +static __le64 pack_value(dm_oblock_t block, unsigned int flags) +{ + uint64_t value = from_oblock(block); + + value <<= 16; + value = value | (flags & FLAGS_MASK); + return cpu_to_le64(value); +} + +static void unpack_value(__le64 value_le, dm_oblock_t *block, unsigned int *flags) +{ + uint64_t value = le64_to_cpu(value_le); + uint64_t b = value >> 16; + + *block = to_oblock(b); + *flags = value & FLAGS_MASK; +} + +/*----------------------------------------------------------------*/ + +static struct dm_cache_metadata *metadata_open(struct block_device *bdev, + sector_t data_block_size, + bool may_format_device, + size_t policy_hint_size, + unsigned int metadata_version) +{ + int r; + struct dm_cache_metadata *cmd; + + cmd = kzalloc(sizeof(*cmd), GFP_KERNEL); + if (!cmd) { + DMERR("could not allocate metadata struct"); + return ERR_PTR(-ENOMEM); + } + + cmd->version = metadata_version; + refcount_set(&cmd->ref_count, 1); + init_rwsem(&cmd->root_lock); + cmd->bdev = bdev; + cmd->data_block_size = data_block_size; + cmd->cache_blocks = 0; + cmd->policy_hint_size = policy_hint_size; + cmd->changed = true; + cmd->fail_io = false; + + r = __create_persistent_data_objects(cmd, may_format_device); + if (r) { + kfree(cmd); + return ERR_PTR(r); + } + + r = __begin_transaction_flags(cmd, clear_clean_shutdown); + if (r < 0) { + dm_cache_metadata_close(cmd); + return ERR_PTR(r); + } + + return cmd; +} + +/* + * We keep a little list of ref counted metadata objects to prevent two + * different target instances creating separate bufio instances. This is + * an issue if a table is reloaded before the suspend. + */ +static DEFINE_MUTEX(table_lock); +static LIST_HEAD(table); + +static struct dm_cache_metadata *lookup(struct block_device *bdev) +{ + struct dm_cache_metadata *cmd; + + list_for_each_entry(cmd, &table, list) + if (cmd->bdev == bdev) { + refcount_inc(&cmd->ref_count); + return cmd; + } + + return NULL; +} + +static struct dm_cache_metadata *lookup_or_open(struct block_device *bdev, + sector_t data_block_size, + bool may_format_device, + size_t policy_hint_size, + unsigned int metadata_version) +{ + struct dm_cache_metadata *cmd, *cmd2; + + mutex_lock(&table_lock); + cmd = lookup(bdev); + mutex_unlock(&table_lock); + + if (cmd) + return cmd; + + cmd = metadata_open(bdev, data_block_size, may_format_device, + policy_hint_size, metadata_version); + if (!IS_ERR(cmd)) { + mutex_lock(&table_lock); + cmd2 = lookup(bdev); + if (cmd2) { + mutex_unlock(&table_lock); + __destroy_persistent_data_objects(cmd, true); + kfree(cmd); + return cmd2; + } + list_add(&cmd->list, &table); + mutex_unlock(&table_lock); + } + + return cmd; +} + +static bool same_params(struct dm_cache_metadata *cmd, sector_t data_block_size) +{ + if (cmd->data_block_size != data_block_size) { + DMERR("data_block_size (%llu) different from that in metadata (%llu)", + (unsigned long long) data_block_size, + (unsigned long long) cmd->data_block_size); + return false; + } + + return true; +} + +struct dm_cache_metadata *dm_cache_metadata_open(struct block_device *bdev, + sector_t data_block_size, + bool may_format_device, + size_t policy_hint_size, + unsigned int metadata_version) +{ + struct dm_cache_metadata *cmd = lookup_or_open(bdev, data_block_size, may_format_device, + policy_hint_size, metadata_version); + + if (!IS_ERR(cmd) && !same_params(cmd, data_block_size)) { + dm_cache_metadata_close(cmd); + return ERR_PTR(-EINVAL); + } + + return cmd; +} + +void dm_cache_metadata_close(struct dm_cache_metadata *cmd) +{ + if (refcount_dec_and_test(&cmd->ref_count)) { + mutex_lock(&table_lock); + list_del(&cmd->list); + mutex_unlock(&table_lock); + + if (!cmd->fail_io) + __destroy_persistent_data_objects(cmd, true); + kfree(cmd); + } +} + +/* + * Checks that the given cache block is either unmapped or clean. + */ +static int block_clean_combined_dirty(struct dm_cache_metadata *cmd, dm_cblock_t b, + bool *result) +{ + int r; + __le64 value; + dm_oblock_t ob; + unsigned int flags; + + r = dm_array_get_value(&cmd->info, cmd->root, from_cblock(b), &value); + if (r) + return r; + + unpack_value(value, &ob, &flags); + *result = !((flags & M_VALID) && (flags & M_DIRTY)); + + return 0; +} + +static int blocks_are_clean_combined_dirty(struct dm_cache_metadata *cmd, + dm_cblock_t begin, dm_cblock_t end, + bool *result) +{ + int r; + *result = true; + + while (begin != end) { + r = block_clean_combined_dirty(cmd, begin, result); + if (r) { + DMERR("block_clean_combined_dirty failed"); + return r; + } + + if (!*result) { + DMERR("cache block %llu is dirty", + (unsigned long long) from_cblock(begin)); + return 0; + } + + begin = to_cblock(from_cblock(begin) + 1); + } + + return 0; +} + +static int blocks_are_clean_separate_dirty(struct dm_cache_metadata *cmd, + dm_cblock_t begin, dm_cblock_t end, + bool *result) +{ + int r; + bool dirty_flag; + *result = true; + + if (from_cblock(cmd->cache_blocks) == 0) + /* Nothing to do */ + return 0; + + r = dm_bitset_cursor_begin(&cmd->dirty_info, cmd->dirty_root, + from_cblock(cmd->cache_blocks), &cmd->dirty_cursor); + if (r) { + DMERR("%s: dm_bitset_cursor_begin for dirty failed", __func__); + return r; + } + + r = dm_bitset_cursor_skip(&cmd->dirty_cursor, from_cblock(begin)); + if (r) { + DMERR("%s: dm_bitset_cursor_skip for dirty failed", __func__); + dm_bitset_cursor_end(&cmd->dirty_cursor); + return r; + } + + while (begin != end) { + /* + * We assume that unmapped blocks have their dirty bit + * cleared. + */ + dirty_flag = dm_bitset_cursor_get_value(&cmd->dirty_cursor); + if (dirty_flag) { + DMERR("%s: cache block %llu is dirty", __func__, + (unsigned long long) from_cblock(begin)); + dm_bitset_cursor_end(&cmd->dirty_cursor); + *result = false; + return 0; + } + + begin = to_cblock(from_cblock(begin) + 1); + if (begin == end) + break; + + r = dm_bitset_cursor_next(&cmd->dirty_cursor); + if (r) { + DMERR("%s: dm_bitset_cursor_next for dirty failed", __func__); + dm_bitset_cursor_end(&cmd->dirty_cursor); + return r; + } + } + + dm_bitset_cursor_end(&cmd->dirty_cursor); + + return 0; +} + +static int blocks_are_unmapped_or_clean(struct dm_cache_metadata *cmd, + dm_cblock_t begin, dm_cblock_t end, + bool *result) +{ + if (separate_dirty_bits(cmd)) + return blocks_are_clean_separate_dirty(cmd, begin, end, result); + else + return blocks_are_clean_combined_dirty(cmd, begin, end, result); +} + +static bool cmd_write_lock(struct dm_cache_metadata *cmd) +{ + down_write(&cmd->root_lock); + if (cmd->fail_io || dm_bm_is_read_only(cmd->bm)) { + up_write(&cmd->root_lock); + return false; + } + return true; +} + +#define WRITE_LOCK(cmd) \ + do { \ + if (!cmd_write_lock((cmd))) \ + return -EINVAL; \ + } while (0) + +#define WRITE_LOCK_VOID(cmd) \ + do { \ + if (!cmd_write_lock((cmd))) \ + return; \ + } while (0) + +#define WRITE_UNLOCK(cmd) \ + up_write(&(cmd)->root_lock) + +static bool cmd_read_lock(struct dm_cache_metadata *cmd) +{ + down_read(&cmd->root_lock); + if (cmd->fail_io) { + up_read(&cmd->root_lock); + return false; + } + return true; +} + +#define READ_LOCK(cmd) \ + do { \ + if (!cmd_read_lock((cmd))) \ + return -EINVAL; \ + } while (0) + +#define READ_LOCK_VOID(cmd) \ + do { \ + if (!cmd_read_lock((cmd))) \ + return; \ + } while (0) + +#define READ_UNLOCK(cmd) \ + up_read(&(cmd)->root_lock) + +int dm_cache_resize(struct dm_cache_metadata *cmd, dm_cblock_t new_cache_size) +{ + int r; + bool clean; + __le64 null_mapping = pack_value(0, 0); + + WRITE_LOCK(cmd); + __dm_bless_for_disk(&null_mapping); + + if (from_cblock(new_cache_size) < from_cblock(cmd->cache_blocks)) { + r = blocks_are_unmapped_or_clean(cmd, new_cache_size, cmd->cache_blocks, &clean); + if (r) { + __dm_unbless_for_disk(&null_mapping); + goto out; + } + + if (!clean) { + DMERR("unable to shrink cache due to dirty blocks"); + r = -EINVAL; + __dm_unbless_for_disk(&null_mapping); + goto out; + } + } + + r = dm_array_resize(&cmd->info, cmd->root, from_cblock(cmd->cache_blocks), + from_cblock(new_cache_size), + &null_mapping, &cmd->root); + if (r) + goto out; + + if (separate_dirty_bits(cmd)) { + r = dm_bitset_resize(&cmd->dirty_info, cmd->dirty_root, + from_cblock(cmd->cache_blocks), from_cblock(new_cache_size), + false, &cmd->dirty_root); + if (r) + goto out; + } + + cmd->cache_blocks = new_cache_size; + cmd->changed = true; + +out: + WRITE_UNLOCK(cmd); + + return r; +} + +int dm_cache_discard_bitset_resize(struct dm_cache_metadata *cmd, + sector_t discard_block_size, + dm_dblock_t new_nr_entries) +{ + int r; + + WRITE_LOCK(cmd); + r = dm_bitset_resize(&cmd->discard_info, + cmd->discard_root, + from_dblock(cmd->discard_nr_blocks), + from_dblock(new_nr_entries), + false, &cmd->discard_root); + if (!r) { + cmd->discard_block_size = discard_block_size; + cmd->discard_nr_blocks = new_nr_entries; + } + + cmd->changed = true; + WRITE_UNLOCK(cmd); + + return r; +} + +static int __set_discard(struct dm_cache_metadata *cmd, dm_dblock_t b) +{ + return dm_bitset_set_bit(&cmd->discard_info, cmd->discard_root, + from_dblock(b), &cmd->discard_root); +} + +static int __clear_discard(struct dm_cache_metadata *cmd, dm_dblock_t b) +{ + return dm_bitset_clear_bit(&cmd->discard_info, cmd->discard_root, + from_dblock(b), &cmd->discard_root); +} + +static int __discard(struct dm_cache_metadata *cmd, + dm_dblock_t dblock, bool discard) +{ + int r; + + r = (discard ? __set_discard : __clear_discard)(cmd, dblock); + if (r) + return r; + + cmd->changed = true; + return 0; +} + +int dm_cache_set_discard(struct dm_cache_metadata *cmd, + dm_dblock_t dblock, bool discard) +{ + int r; + + WRITE_LOCK(cmd); + r = __discard(cmd, dblock, discard); + WRITE_UNLOCK(cmd); + + return r; +} + +static int __load_discards(struct dm_cache_metadata *cmd, + load_discard_fn fn, void *context) +{ + int r = 0; + uint32_t b; + struct dm_bitset_cursor c; + + if (from_dblock(cmd->discard_nr_blocks) == 0) + /* nothing to do */ + return 0; + + if (cmd->clean_when_opened) { + r = dm_bitset_flush(&cmd->discard_info, cmd->discard_root, &cmd->discard_root); + if (r) + return r; + + r = dm_bitset_cursor_begin(&cmd->discard_info, cmd->discard_root, + from_dblock(cmd->discard_nr_blocks), &c); + if (r) + return r; + + for (b = 0; ; b++) { + r = fn(context, cmd->discard_block_size, to_dblock(b), + dm_bitset_cursor_get_value(&c)); + if (r) + break; + + if (b >= (from_dblock(cmd->discard_nr_blocks) - 1)) + break; + + r = dm_bitset_cursor_next(&c); + if (r) + break; + } + + dm_bitset_cursor_end(&c); + + } else { + for (b = 0; b < from_dblock(cmd->discard_nr_blocks); b++) { + r = fn(context, cmd->discard_block_size, to_dblock(b), false); + if (r) + return r; + } + } + + return r; +} + +int dm_cache_load_discards(struct dm_cache_metadata *cmd, + load_discard_fn fn, void *context) +{ + int r; + + READ_LOCK(cmd); + r = __load_discards(cmd, fn, context); + READ_UNLOCK(cmd); + + return r; +} + +int dm_cache_size(struct dm_cache_metadata *cmd, dm_cblock_t *result) +{ + READ_LOCK(cmd); + *result = cmd->cache_blocks; + READ_UNLOCK(cmd); + + return 0; +} + +static int __remove(struct dm_cache_metadata *cmd, dm_cblock_t cblock) +{ + int r; + __le64 value = pack_value(0, 0); + + __dm_bless_for_disk(&value); + r = dm_array_set_value(&cmd->info, cmd->root, from_cblock(cblock), + &value, &cmd->root); + if (r) + return r; + + cmd->changed = true; + return 0; +} + +int dm_cache_remove_mapping(struct dm_cache_metadata *cmd, dm_cblock_t cblock) +{ + int r; + + WRITE_LOCK(cmd); + r = __remove(cmd, cblock); + WRITE_UNLOCK(cmd); + + return r; +} + +static int __insert(struct dm_cache_metadata *cmd, + dm_cblock_t cblock, dm_oblock_t oblock) +{ + int r; + __le64 value = pack_value(oblock, M_VALID); + + __dm_bless_for_disk(&value); + + r = dm_array_set_value(&cmd->info, cmd->root, from_cblock(cblock), + &value, &cmd->root); + if (r) + return r; + + cmd->changed = true; + return 0; +} + +int dm_cache_insert_mapping(struct dm_cache_metadata *cmd, + dm_cblock_t cblock, dm_oblock_t oblock) +{ + int r; + + WRITE_LOCK(cmd); + r = __insert(cmd, cblock, oblock); + WRITE_UNLOCK(cmd); + + return r; +} + +struct thunk { + load_mapping_fn fn; + void *context; + + struct dm_cache_metadata *cmd; + bool respect_dirty_flags; + bool hints_valid; +}; + +static bool policy_unchanged(struct dm_cache_metadata *cmd, + struct dm_cache_policy *policy) +{ + const char *policy_name = dm_cache_policy_get_name(policy); + const unsigned int *policy_version = dm_cache_policy_get_version(policy); + size_t policy_hint_size = dm_cache_policy_get_hint_size(policy); + + /* + * Ensure policy names match. + */ + if (strncmp(cmd->policy_name, policy_name, sizeof(cmd->policy_name))) + return false; + + /* + * Ensure policy major versions match. + */ + if (cmd->policy_version[0] != policy_version[0]) + return false; + + /* + * Ensure policy hint sizes match. + */ + if (cmd->policy_hint_size != policy_hint_size) + return false; + + return true; +} + +static bool hints_array_initialized(struct dm_cache_metadata *cmd) +{ + return cmd->hint_root && cmd->policy_hint_size; +} + +static bool hints_array_available(struct dm_cache_metadata *cmd, + struct dm_cache_policy *policy) +{ + return cmd->clean_when_opened && policy_unchanged(cmd, policy) && + hints_array_initialized(cmd); +} + +static int __load_mapping_v1(struct dm_cache_metadata *cmd, + uint64_t cb, bool hints_valid, + struct dm_array_cursor *mapping_cursor, + struct dm_array_cursor *hint_cursor, + load_mapping_fn fn, void *context) +{ + int r = 0; + + __le64 mapping; + __le32 hint = 0; + + __le64 *mapping_value_le; + __le32 *hint_value_le; + + dm_oblock_t oblock; + unsigned int flags; + bool dirty = true; + + dm_array_cursor_get_value(mapping_cursor, (void **) &mapping_value_le); + memcpy(&mapping, mapping_value_le, sizeof(mapping)); + unpack_value(mapping, &oblock, &flags); + + if (flags & M_VALID) { + if (hints_valid) { + dm_array_cursor_get_value(hint_cursor, (void **) &hint_value_le); + memcpy(&hint, hint_value_le, sizeof(hint)); + } + if (cmd->clean_when_opened) + dirty = flags & M_DIRTY; + + r = fn(context, oblock, to_cblock(cb), dirty, + le32_to_cpu(hint), hints_valid); + if (r) { + DMERR("policy couldn't load cache block %llu", + (unsigned long long) from_cblock(to_cblock(cb))); + } + } + + return r; +} + +static int __load_mapping_v2(struct dm_cache_metadata *cmd, + uint64_t cb, bool hints_valid, + struct dm_array_cursor *mapping_cursor, + struct dm_array_cursor *hint_cursor, + struct dm_bitset_cursor *dirty_cursor, + load_mapping_fn fn, void *context) +{ + int r = 0; + + __le64 mapping; + __le32 hint = 0; + + __le64 *mapping_value_le; + __le32 *hint_value_le; + + dm_oblock_t oblock; + unsigned int flags; + bool dirty = true; + + dm_array_cursor_get_value(mapping_cursor, (void **) &mapping_value_le); + memcpy(&mapping, mapping_value_le, sizeof(mapping)); + unpack_value(mapping, &oblock, &flags); + + if (flags & M_VALID) { + if (hints_valid) { + dm_array_cursor_get_value(hint_cursor, (void **) &hint_value_le); + memcpy(&hint, hint_value_le, sizeof(hint)); + } + if (cmd->clean_when_opened) + dirty = dm_bitset_cursor_get_value(dirty_cursor); + + r = fn(context, oblock, to_cblock(cb), dirty, + le32_to_cpu(hint), hints_valid); + if (r) { + DMERR("policy couldn't load cache block %llu", + (unsigned long long) from_cblock(to_cblock(cb))); + } + } + + return r; +} + +static int __load_mappings(struct dm_cache_metadata *cmd, + struct dm_cache_policy *policy, + load_mapping_fn fn, void *context) +{ + int r; + uint64_t cb; + + bool hints_valid = hints_array_available(cmd, policy); + + if (from_cblock(cmd->cache_blocks) == 0) + /* Nothing to do */ + return 0; + + r = dm_array_cursor_begin(&cmd->info, cmd->root, &cmd->mapping_cursor); + if (r) + return r; + + if (hints_valid) { + r = dm_array_cursor_begin(&cmd->hint_info, cmd->hint_root, &cmd->hint_cursor); + if (r) { + dm_array_cursor_end(&cmd->mapping_cursor); + return r; + } + } + + if (separate_dirty_bits(cmd)) { + r = dm_bitset_cursor_begin(&cmd->dirty_info, cmd->dirty_root, + from_cblock(cmd->cache_blocks), + &cmd->dirty_cursor); + if (r) { + dm_array_cursor_end(&cmd->hint_cursor); + dm_array_cursor_end(&cmd->mapping_cursor); + return r; + } + } + + for (cb = 0; ; cb++) { + if (separate_dirty_bits(cmd)) + r = __load_mapping_v2(cmd, cb, hints_valid, + &cmd->mapping_cursor, + &cmd->hint_cursor, + &cmd->dirty_cursor, + fn, context); + else + r = __load_mapping_v1(cmd, cb, hints_valid, + &cmd->mapping_cursor, &cmd->hint_cursor, + fn, context); + if (r) + goto out; + + /* + * We need to break out before we move the cursors. + */ + if (cb >= (from_cblock(cmd->cache_blocks) - 1)) + break; + + r = dm_array_cursor_next(&cmd->mapping_cursor); + if (r) { + DMERR("dm_array_cursor_next for mapping failed"); + goto out; + } + + if (hints_valid) { + r = dm_array_cursor_next(&cmd->hint_cursor); + if (r) { + dm_array_cursor_end(&cmd->hint_cursor); + hints_valid = false; + } + } + + if (separate_dirty_bits(cmd)) { + r = dm_bitset_cursor_next(&cmd->dirty_cursor); + if (r) { + DMERR("dm_bitset_cursor_next for dirty failed"); + goto out; + } + } + } +out: + dm_array_cursor_end(&cmd->mapping_cursor); + if (hints_valid) + dm_array_cursor_end(&cmd->hint_cursor); + + if (separate_dirty_bits(cmd)) + dm_bitset_cursor_end(&cmd->dirty_cursor); + + return r; +} + +int dm_cache_load_mappings(struct dm_cache_metadata *cmd, + struct dm_cache_policy *policy, + load_mapping_fn fn, void *context) +{ + int r; + + READ_LOCK(cmd); + r = __load_mappings(cmd, policy, fn, context); + READ_UNLOCK(cmd); + + return r; +} + +static int __dump_mapping(void *context, uint64_t cblock, void *leaf) +{ + __le64 value; + dm_oblock_t oblock; + unsigned int flags; + + memcpy(&value, leaf, sizeof(value)); + unpack_value(value, &oblock, &flags); + + return 0; +} + +static int __dump_mappings(struct dm_cache_metadata *cmd) +{ + return dm_array_walk(&cmd->info, cmd->root, __dump_mapping, NULL); +} + +void dm_cache_dump(struct dm_cache_metadata *cmd) +{ + READ_LOCK_VOID(cmd); + __dump_mappings(cmd); + READ_UNLOCK(cmd); +} + +int dm_cache_changed_this_transaction(struct dm_cache_metadata *cmd) +{ + int r; + + READ_LOCK(cmd); + r = cmd->changed; + READ_UNLOCK(cmd); + + return r; +} + +static int __dirty(struct dm_cache_metadata *cmd, dm_cblock_t cblock, bool dirty) +{ + int r; + unsigned int flags; + dm_oblock_t oblock; + __le64 value; + + r = dm_array_get_value(&cmd->info, cmd->root, from_cblock(cblock), &value); + if (r) + return r; + + unpack_value(value, &oblock, &flags); + + if (((flags & M_DIRTY) && dirty) || (!(flags & M_DIRTY) && !dirty)) + /* nothing to be done */ + return 0; + + value = pack_value(oblock, (flags & ~M_DIRTY) | (dirty ? M_DIRTY : 0)); + __dm_bless_for_disk(&value); + + r = dm_array_set_value(&cmd->info, cmd->root, from_cblock(cblock), + &value, &cmd->root); + if (r) + return r; + + cmd->changed = true; + return 0; + +} + +static int __set_dirty_bits_v1(struct dm_cache_metadata *cmd, unsigned int nr_bits, unsigned long *bits) +{ + int r; + unsigned int i; + + for (i = 0; i < nr_bits; i++) { + r = __dirty(cmd, to_cblock(i), test_bit(i, bits)); + if (r) + return r; + } + + return 0; +} + +static int is_dirty_callback(uint32_t index, bool *value, void *context) +{ + unsigned long *bits = context; + *value = test_bit(index, bits); + return 0; +} + +static int __set_dirty_bits_v2(struct dm_cache_metadata *cmd, unsigned int nr_bits, unsigned long *bits) +{ + int r = 0; + + /* nr_bits is really just a sanity check */ + if (nr_bits != from_cblock(cmd->cache_blocks)) { + DMERR("dirty bitset is wrong size"); + return -EINVAL; + } + + r = dm_bitset_del(&cmd->dirty_info, cmd->dirty_root); + if (r) + return r; + + cmd->changed = true; + return dm_bitset_new(&cmd->dirty_info, &cmd->dirty_root, nr_bits, is_dirty_callback, bits); +} + +int dm_cache_set_dirty_bits(struct dm_cache_metadata *cmd, + unsigned int nr_bits, + unsigned long *bits) +{ + int r; + + WRITE_LOCK(cmd); + if (separate_dirty_bits(cmd)) + r = __set_dirty_bits_v2(cmd, nr_bits, bits); + else + r = __set_dirty_bits_v1(cmd, nr_bits, bits); + WRITE_UNLOCK(cmd); + + return r; +} + +void dm_cache_metadata_get_stats(struct dm_cache_metadata *cmd, + struct dm_cache_statistics *stats) +{ + READ_LOCK_VOID(cmd); + *stats = cmd->stats; + READ_UNLOCK(cmd); +} + +void dm_cache_metadata_set_stats(struct dm_cache_metadata *cmd, + struct dm_cache_statistics *stats) +{ + WRITE_LOCK_VOID(cmd); + cmd->stats = *stats; + WRITE_UNLOCK(cmd); +} + +int dm_cache_commit(struct dm_cache_metadata *cmd, bool clean_shutdown) +{ + int r = -EINVAL; + flags_mutator mutator = (clean_shutdown ? set_clean_shutdown : + clear_clean_shutdown); + + WRITE_LOCK(cmd); + if (cmd->fail_io) + goto out; + + r = __commit_transaction(cmd, mutator); + if (r) + goto out; + + r = __begin_transaction(cmd); +out: + WRITE_UNLOCK(cmd); + return r; +} + +int dm_cache_get_free_metadata_block_count(struct dm_cache_metadata *cmd, + dm_block_t *result) +{ + int r = -EINVAL; + + READ_LOCK(cmd); + if (!cmd->fail_io) + r = dm_sm_get_nr_free(cmd->metadata_sm, result); + READ_UNLOCK(cmd); + + return r; +} + +int dm_cache_get_metadata_dev_size(struct dm_cache_metadata *cmd, + dm_block_t *result) +{ + int r = -EINVAL; + + READ_LOCK(cmd); + if (!cmd->fail_io) + r = dm_sm_get_nr_blocks(cmd->metadata_sm, result); + READ_UNLOCK(cmd); + + return r; +} + +/*----------------------------------------------------------------*/ + +static int get_hint(uint32_t index, void *value_le, void *context) +{ + uint32_t value; + struct dm_cache_policy *policy = context; + + value = policy_get_hint(policy, to_cblock(index)); + *((__le32 *) value_le) = cpu_to_le32(value); + + return 0; +} + +/* + * It's quicker to always delete the hint array, and recreate with + * dm_array_new(). + */ +static int write_hints(struct dm_cache_metadata *cmd, struct dm_cache_policy *policy) +{ + int r; + size_t hint_size; + const char *policy_name = dm_cache_policy_get_name(policy); + const unsigned int *policy_version = dm_cache_policy_get_version(policy); + + if (!policy_name[0] || + (strlen(policy_name) > sizeof(cmd->policy_name) - 1)) + return -EINVAL; + + strncpy(cmd->policy_name, policy_name, sizeof(cmd->policy_name)); + memcpy(cmd->policy_version, policy_version, sizeof(cmd->policy_version)); + + hint_size = dm_cache_policy_get_hint_size(policy); + if (!hint_size) + return 0; /* short-circuit hints initialization */ + cmd->policy_hint_size = hint_size; + + if (cmd->hint_root) { + r = dm_array_del(&cmd->hint_info, cmd->hint_root); + if (r) + return r; + } + + return dm_array_new(&cmd->hint_info, &cmd->hint_root, + from_cblock(cmd->cache_blocks), + get_hint, policy); +} + +int dm_cache_write_hints(struct dm_cache_metadata *cmd, struct dm_cache_policy *policy) +{ + int r; + + WRITE_LOCK(cmd); + r = write_hints(cmd, policy); + WRITE_UNLOCK(cmd); + + return r; +} + +int dm_cache_metadata_all_clean(struct dm_cache_metadata *cmd, bool *result) +{ + int r; + + READ_LOCK(cmd); + r = blocks_are_unmapped_or_clean(cmd, 0, cmd->cache_blocks, result); + READ_UNLOCK(cmd); + + return r; +} + +void dm_cache_metadata_set_read_only(struct dm_cache_metadata *cmd) +{ + WRITE_LOCK_VOID(cmd); + dm_bm_set_read_only(cmd->bm); + WRITE_UNLOCK(cmd); +} + +void dm_cache_metadata_set_read_write(struct dm_cache_metadata *cmd) +{ + WRITE_LOCK_VOID(cmd); + dm_bm_set_read_write(cmd->bm); + WRITE_UNLOCK(cmd); +} + +int dm_cache_metadata_set_needs_check(struct dm_cache_metadata *cmd) +{ + int r; + struct dm_block *sblock; + struct cache_disk_superblock *disk_super; + + WRITE_LOCK(cmd); + set_bit(NEEDS_CHECK, &cmd->flags); + + r = superblock_lock(cmd, &sblock); + if (r) { + DMERR("couldn't read superblock"); + goto out; + } + + disk_super = dm_block_data(sblock); + disk_super->flags = cpu_to_le32(cmd->flags); + + dm_bm_unlock(sblock); + +out: + WRITE_UNLOCK(cmd); + return r; +} + +int dm_cache_metadata_needs_check(struct dm_cache_metadata *cmd, bool *result) +{ + READ_LOCK(cmd); + *result = !!test_bit(NEEDS_CHECK, &cmd->flags); + READ_UNLOCK(cmd); + + return 0; +} + +int dm_cache_metadata_abort(struct dm_cache_metadata *cmd) +{ + int r = -EINVAL; + struct dm_block_manager *old_bm = NULL, *new_bm = NULL; + + /* fail_io is double-checked with cmd->root_lock held below */ + if (unlikely(cmd->fail_io)) + return r; + + /* + * Replacement block manager (new_bm) is created and old_bm destroyed outside of + * cmd root_lock to avoid ABBA deadlock that would result (due to life-cycle of + * shrinker associated with the block manager's bufio client vs cmd root_lock). + * - must take shrinker_rwsem without holding cmd->root_lock + */ + new_bm = dm_block_manager_create(cmd->bdev, DM_CACHE_METADATA_BLOCK_SIZE << SECTOR_SHIFT, + CACHE_MAX_CONCURRENT_LOCKS); + + WRITE_LOCK(cmd); + if (cmd->fail_io) { + WRITE_UNLOCK(cmd); + goto out; + } + + __destroy_persistent_data_objects(cmd, false); + old_bm = cmd->bm; + if (IS_ERR(new_bm)) { + DMERR("could not create block manager during abort"); + cmd->bm = NULL; + r = PTR_ERR(new_bm); + goto out_unlock; + } + + cmd->bm = new_bm; + r = __open_or_format_metadata(cmd, false); + if (r) { + cmd->bm = NULL; + goto out_unlock; + } + new_bm = NULL; +out_unlock: + if (r) + cmd->fail_io = true; + WRITE_UNLOCK(cmd); + dm_block_manager_destroy(old_bm); +out: + if (new_bm && !IS_ERR(new_bm)) + dm_block_manager_destroy(new_bm); + + return r; +} |